Embodiments of the inventive concept relate to mobile systems, and more particularly, to mobile systems including a system-on-chip that receives one or more supply voltage(s) via a merged power rail. The so called system-on-chip (SOC) has become a staple component in many contemporary electrical systems and electronic devices. A SOC typically includes multiple circuit blocks, such as an application processor (AP) and a communication processor (CP). Each circuit block will have its own power consumption characteristics, and over time the level and nature of one or more power supply voltage(s) provided to a circuit block will vary with particular use. That is, power consumption at any given moment in operating time may vary between circuit blocks. In contemporary mobile systems, the provision and control of power supply voltage(s) relative to respective circuit blocks is substantially independent. That is, the supply, monitoring and regulation of power supply voltages with respect to each circuit block is uncorrelated, or controlled at a relatively high control level. This creates control delays and resulting inefficiencies in the conservation of power—an important function in mobile systems. Furthermore, multiple power rails have been used to provide power supply voltages to respective circuit blocks. This drives up the overall size of the constituent system. More recently, the possibility of providing one or more supply voltage(s) to multiple circuit blocks in a SOC via a single power rail has been investigated.